OS Update/ JVM Error

My phone gave me the ****, with the JVM 547 error.
I have my phone in, the Mac DM ready to go... and is aware that the 4.5 OS needs to be installed on my 8310.
It will enter the updating screen, but does not update - no movement on the progress bar. After about a minute an error comes up saying the device has been disconnected, and to try again.